U.S. patent application number 11/176050 was filed with the patent office on 2006-04-27 for trigger sprayer venting system with reduced drag on vent piston.
This patent application is currently assigned to Continental AFA Dispensing Company. Invention is credited to Donald D. Foster.
Application Number | 20060086763 11/176050 |
Document ID | / |
Family ID | 36148764 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060086763 |
Kind Code |
A1 |
Foster; Donald D. |
April 27, 2006 |
Trigger sprayer venting system with reduced drag on vent piston
Abstract
A venting system of a manually operated trigger sprayer vents
the interior of a liquid container connected to the trigger
sprayer. The trigger sprayer is provided with a vent chamber that
surrounds the pump chamber, and a vent piston that surrounds the
pump piston. The vent piston is received in the vent chamber for
reciprocating movements between a vent closed and vent opened
position in the vent chamber, and the vent chamber having two
different interior diameter sections with a larger interior
diameter section reducing drag on the vent piston when the vent
piston is moved to the vent opened position.
Inventors: |
Foster; Donald D.; (St.
Charles, MO) |
Correspondence
Address: |
THOMPSON COBURN, LLP
ONE US BANK PLAZA
SUITE 3500
ST LOUIS
MO
63101
US
|
Assignee: |
Continental AFA Dispensing
Company
|
Family ID: |
36148764 |
Appl. No.: |
11/176050 |
Filed: |
July 7, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10961286 |
Oct 8, 2004 |
|
|
|
11176050 |
Jul 7, 2005 |
|
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Current U.S.
Class: |
222/383.1 |
Current CPC
Class: |
B05B 11/3074 20130101;
B05B 11/3011 20130101; B05B 11/3077 20130101; B05B 11/0044
20180801 |
Class at
Publication: |
222/383.1 |
International
Class: |
B67D 5/40 20060101
B67D005/40 |
Claims
1. A manually operated, liquid dispensing trigger sprayer
comprising: a sprayer housing; a liquid pump on the sprayer
housing, the liquid pump including a pump chamber and a liquid
piston mounted in the pump chamber for reciprocating movements of
the liquid piston between first and second positions of the liquid
piston in the pump chamber on operation of the liquid pump; a
liquid discharge passage extending through the sprayer housing and
communicating with the liquid pump for directing liquid from the
liquid pump, through the sprayer housing, and discharging the
liquid from the sprayer housing on operation of the liquid pump; a
trigger mounted on the sprayer housing for movement of the trigger
relative to the sprayer housing, the trigger being operatively
connected to the liquid pump for operation of the liquid pump in
response to movement of the trigger; and, a vent chamber on the
sprayer housing, the vent chamber having a cylindrical interior
surface that extends around the liquid pump, the vent chamber
interior surface having opposite first and second end sections with
respective first and second interior diameter dimensions, the first
interior diameter dimension being smaller than a second interior
diameter dimension.
2. The trigger sprayer of claim 1, further comprising: the pump
chamber having a cylindrical sidewall; and, the vent chamber having
a cylindrical sidewall that extends around the pump chamber
sidewall with the pump chamber sidewall contained inside the vent
chamber sidewall.
3. The trigger sprayer of claim 2, further comprising: a vent
opening through the vent chamber sidewall; and, the pump chamber
sidewall overlapping the vent opening.
4. The trigger sprayer of claim 1, further comprising: the liquid
pump having a pump chamber with a cylindrical interior surface, and
a pump piston mounted in the pump chamber for reciprocating
movement relative to the pump chamber; and, a vent piston
operatively connected to the pump piston and mounted in the vent
chamber for reciprocating movement relative to the vent
chamber.
5. The trigger sprayer of claim 4, further comprising: the pump
chamber being positioned inside the vent chamber interior
surface.
6. The trigger sprayer of claim 4, further comprising: the vent
chamber interior surface extending around the pump chamber.
7. The trigger sprayer of claim 4, further comprising: the pump
piston being positioned inside the vent piston.
8. The trigger sprayer of claim 4, further comprising: the vent
piston extending around the pump piston.
9. The trigger sprayer of claim 4, further comprising: the vent
piston being moveable in the vent chamber between first and second
axially spaced positions of the vent piston in the vent chamber,
the vent piston engaging against the vent chamber interior surface
in the first position of the vent piston and the vent piston
engaging with the vent chamber interior surface when the vent
piston is moved to the second position of the vent piston.
10. A manually operated liquid dispensing trigger sprayer
comprising: a sprayer housing; a liquid pump chamber having a pump
chamber sidewall on the sprayer housing; a vent chamber having a
vent chamber sidewall on the sprayer housing, the vent chamber
sidewall extending around the pump chamber sidewall and surrounding
the pump chamber, the vent chamber sidewall having a first section
with a first interior diameter dimension and a second section with
a second interior diameter dimension, the second interior diameter
dimension being larger than the first interior diameter dimension;
a liquid discharge passage extending through the sprayer housing
and communicating with the pump chamber for directing liquid from
the pump chamber, through the sprayer housing, and discharging the
liquid from the sprayer housing; a pump piston mounted in the pump
chamber for reciprocating movement of the pump piston in the pump
chamber; a vent piston mounted in the vent chamber for
reciprocating movement of the vent piston in the vent chamber; and,
a trigger mounted on the sprayer housing for movement of the
trigger relative to the sprayer housing, the trigger being
operatively connected to the pump piston and the vent piston for
reciprocating movement of the pump piston and vent piston in the
respective pump chamber and vent chamber in response to movement of
the trigger.
11. The trigger sprayer of claim 10, further comprising: the pump
chamber sidewall having a cylindrical interior surface with a
center axis; the vent chamber sidewall having a cylindrical
interior surface with a center axis; and, the pump chamber center
axis being coaxial with the vent chamber center axis.
12. The trigger sprayer of claim 10, further comprising: the pump
piston being positioned inside the vent piston.
13. The trigger sprayer of claim 10, further comprising: the vent
piston having an axial length and the pump piston having an axial
length, with the pump piston axial length being larger than the
vent piston axial length.
14. The trigger sprayer of claim 14, further comprising: the pump
chamber having a cylindrical sidewall; and, the vent chamber having
a cylindrical sidewall that extends around the pump chamber
sidewall with the pump chamber sidewall contained inside the vent
chamber sidewall.
15. The trigger sprayer of claim 14, further comprising: a vent
opening through the vent chamber sidewall; and, the pump chamber
sidewall overlapping the vent opening.
16. A manually operated liquid dispensing trigger sprayer
comprising: a sprayer housing; a liquid pump chamber on the sprayer
housing; a vent chamber on the sprayer housing, the vent chamber
having a cylindrical sidewall that extends around the liquid pump
chamber with the liquid pump chamber being contained entirely
inside the vent chamber sidewall; a liquid discharge passage
communicating with the liquid pump chamber and extending through
the sprayer housing for directing liquid from the pump chamber,
through the sprayer housing, and discharging the liquid from the
sprayer housing; a pump piston mounted in the pump chamber for
reciprocating movement of the pump piston in the pump chamber, the
pump piston being cylindrical and having a center axis; a vent
piston mounted in the vent chamber for reciprocating movement of
the vent piston in the vent chamber, the vent piston being
cylindrical and having a center axis that is coaxial with the pump
piston center axis; and, a trigger mounted on the sprayer housing
for movement of the trigger relative to the sprayer housing, the
trigger being operatively connected to the pump piston and the vent
piston for reciprocating movement of the pump piston and vent
piston in the respective pump chamber and vent chamber in response
to movement of the trigger.
17. The trigger sprayer of claim 16, further comprising: the vent
chamber sidewall having a first section with a first interior
diameter dimension and a second section with a second interior
diameter dimension, the second interior diameter dimension being
larger than the first interior diameter dimension.
18. The trigger sprayer of claim 17, further comprising: the pump
chamber having a cylindrical sidewall that is contained inside and
spaced inwardly from the vent chamber sidewall.
19. The trigger sprayer of claim 16, further comprising: the vent
opening in the vent chamber sidewall, the pump chamber extending
over the vent opening.
20. The trigger sprayer of claim 16, further comprising: the pump
chamber having a cylindrical sidewall; and, a vent opening in the
vent chamber sidewall, the pump chamber sidewall overlapping the
vent opening.
Description
[0001] This patent application is a continuation-in-part of patent
application Ser. No. 10/961,286, which was filed on Oct. 8, 2004,
and is currently pending.
BACKGROUND OF THE INVENTION
[0002] (1) Field of the Invention
[0003] The present invention pertains to a venting system for a
manually operated, liquid dispensing trigger sprayer. More
specifically, the present invention pertains to improvements to a
venting system of a manually operated trigger sprayer that vents
the interior of a liquid container connected to the trigger
sprayer. For the most part, the construction of the trigger sprayer
is typical. The improvement comprises a vent chamber that surrounds
the pump chamber and a vent piston that surrounds the pump piston.
The vent piston is received in the vent chamber for reciprocating
movements with the pump piston in the pump chamber. The
reciprocating movement of the vent piston alternatively opens the
vent chamber to the exterior environment of the trigger sprayer and
thereby vents the interior of the liquid container connected to the
trigger sprayer, and closes the vent chamber thereby sealing the
interior of the liquid container from the exterior environment. The
interior of the vent chamber has a novel configuration where the
interior diameter of the vent chamber gets larger as the vent
chamber extends from a forward portion of the vent chamber toward a
rearward portion of the vent chamber. This reduces the drag or
friction between the peripheral sealing edge of the vent piston and
the interior surface of the vent chamber as the vent piston moves
from the forward portion of the vent chamber toward the rearward
portion of the vent chamber.
[0004] (2) Description of the Related Art
[0005] A typical manually operated liquid dispensing trigger
sprayer comprises a sprayer housing that has a nozzle for
dispensing liquid, a trigger mounted on the sprayer housing for
movement of the trigger relevant to the housing, a pump chamber on
the housing, and a pump piston operatively connected to the trigger
and received in the pump chamber for reciprocating movement of the
piston in the pump chamber in response to manual movement of the
trigger, and a connector attaching the trigger sprayer to a liquid
container. The reciprocating movement of the pump piston in the
pump chamber alternately draws liquid from the liquid container
into the pump chamber, and then pumps the liquid out of the pump
chamber and dispenses the liquid through the nozzle of the sprayer
housing as a spray or stream.
[0006] Trigger sprayers of this type are often provided with some
system of venting the interior of the liquid container connected to
the trigger sprayer. This allows air to enter the container
interior and occupy that portion of the internal volume of the
container that is vacated by the liquid dispensed from the
container by the trigger sprayer.
[0007] Many different types of trigger sprayer venting systems have
been developed in the prior art. One type of venting system employs
a resilient diaphragm valve that is positioned in the interior of
the sprayer housing covering over a vent hole in the sprayer
housing. The vent hole communicates the interior of the sprayer
housing and the interior of the connected liquid container with the
exterior environment of the sprayer. A plunger is provided on the
trigger member of the trigger sprayer. The plunger projects from
the bottom of the pump piston rod and curves toward the sprayer
housing with a distal end of the plunger being positioned just
outside of the vent hole. On manual manipulation of the trigger,
the plunger end is inserted through the vent hole and engages the
diaphragm valve, displacing the diaphragm valve from its position
over the vent hole. This vents the interior of the liquid
container. On the return movement of the trigger the plunger is
retracted out of the vent hole and the resilience of the diaphragm
valve allows it to resume its position over the vent hole.
[0008] However, this prior art venting system has been found to be
disadvantaged in that repeated use of the trigger sprayer causes
repeated displacement of the diaphragm valve from the sprayer vent
hole. The resiliency of the diaphragm valve is effected by these
repeated displacements and the valve is no longer able to
immediately reposition itself over the vent hole once the plunger
is retracted from the vent hole. This can result in liquid leaking
from the container through the vent hole should the container and
trigger sprayer be knocked over on one side before the diaphragm
valve repositions itself over the vent hole. In addition, the
plunger projecting from the piston rod is considered by many to
detract from the appearance of the sprayer and is undesirable.
[0009] Another type of venting system employs a vent cylinder on
the sprayer housing and a vent piston operatively connected to the
trigger of the trigger sprayer. The vent piston, like the
previously described plunger, projects from the pump piston rod.
The vent hole is positioned in the side of the vent cylinder and
one or more small ribs are formed on the interior surface of the
vent cylinder in the area of the vent hole. The vent piston curves
beneath the pump piston rod and extends into the vent cylinder
where the vent piston engages in a sliding, sealing engagement with
the interior surface of the vent cylinder. As the trigger is
manipulated, the vent piston is pushed through the vent cylinder
toward the vent hole and the ribs. The ribs engage with the
periphery of the vent piston and displace the periphery from the
interior surface of the vent cylinder, thereby communicating the
exterior environment of the trigger sprayer around the piston and
through the vent cylinder and the vent hole to the interior of the
liquid container.
[0010] This venting system has been found to be disadvantaged in
that is has the same unappealing appearance of the plunger. Also,
after repeated use of the trigger sprayer, the ribs in the vent
cylinder have a tendency to deform the resilient material around
the periphery of the vent piston. This detracts from the ability of
the vent piston to seal against the interior surface of the vent
cylinder, and can result in leakage of liquid from the liquid
container through the vent cylinder.
[0011] Trigger sprayer designs have eliminated the projecting
plunger or vent piston rod that detracts from the overall
appearance of the trigger sprayer. These designs employ a vent
piston that is coaxial with the pump piston of the trigger sprayer,
and is moved by the pump piston rod of the trigger sprayer. The
vent piston is moved through a vent chamber that is coaxial with
the trigger sprayer pump chamber. This double piston design is more
desirable because it eliminates the separate plunger arm or vent
piston arm from the pump piston rod.
[0012] However, the sliding engagement or rubbing of the vent
piston peripheral sealing surface across the cylindrical interior
surface of the vent chamber as the trigger sprayer pump is operated
often causes swelling of the material of the vent piston. This
swelling of the vent piston can bind the vent piston in the vent
chamber, making it difficult or uncomfortable to push the vent
piston into the vent chamber, and at times preventing the vent
piston from being pushed back out of the vent chamber by the pump
spring. What is needed to overcome this disadvantage of trigger
sprayers having coaxial pump and vent chambers is a redesign of the
venting system that eliminates the cause of vent piston swelling,
and thereby prevents binding of the vent piston in the vent
chamber.
SUMMARY OF THE INVENTION
[0013] The present invention overcomes disadvantages associated
with prior art venting systems of trigger sprayers by providing an
improved trigger sprayer venting system that vents air to the
liquid container connected to the trigger sprayer and prevents
liquid from leaking through the venting system should the trigger
sprayer and liquid container be turned on one side, where the
venting system eliminates the undesirable appearance of the vent
plunger or vent piston employed in the prior art, and the venting
system eliminates the problem of the vent piston sticking in the
vent chamber by eliminating swelling of the vent piston and the
vent chamber wall.
[0014] Much of the construction of the trigger sprayer of the
invention is common to trigger sprayers. The trigger sprayer is
generally constructed with a sprayer housing that is connected by a
separate connector to a fluid container. The sprayer housing is
formed with a liquid pump chamber that communicates with a liquid
supply passage and a liquid discharge passage. A pump piston is
mounted in the pump chamber for reciprocating movement. A trigger
is mounted on the sprayer housing for manual manipulation. The
trigger is operatively connected with the pump piston, and
manipulation of the trigger reciprocates the pump piston in the
pump chamber. Reciprocation of the pump piston alternatively draws
liquid from the liquid container, through the liquid supply
passage, and to the pump chamber, and then pumps the liquid from
the pump chamber, through the liquid discharge passage, and
dispenses the liquid from the sprayer housing as a spray or
stream.
[0015] The trigger sprayer of the invention differs in construction
from that of prior art trigger sprayers in the venting system
provided on the trigger sprayer. The venting system is basically
comprised of a vent chamber, and a vent piston received inside the
vent chamber for reciprocating movement of the vent piston relative
to the vent chamber.
[0016] The vent chamber is formed on the sprayer housing around the
pump chamber of the trigger sprayer. The vent chamber has a
cylindrical side wall that extends around and surrounds the pump
chamber. This coaxial positioning of the pump chamber and vent
chamber relative to each other eliminates the undesirable
appearance of the vent plunger or vent piston rod of the trigger
sprayer. A vent hole is provided in the sidewall of the vent
chamber. The vent hole communicates the interior volume of the vent
chamber with the interior of the liquid container connected to the
trigger sprayer.
[0017] The vent chamber sidewall has a cylindrical interior surface
that extends from an open, forward end of the vent chamber to a
closed, rearward end of the vent chamber. The interior surface has
a larger interior diameter dimension adjacent the rearward end of
the vent chamber. The interior diameter dimension remains
consistent for a majority of the length of the vent chamber as the
vent chamber extends from the rearward end toward the forward, open
end of the vent chamber. As the vent chamber approaches the forward
end of the vent chamber, the interior diameter dimension of the
vent chamber interior surface gradually decreases, forming a necked
down interior surface of the vent chamber having a smaller interior
diameter dimension adjacent the chamber forward end.
[0018] With the vent chamber being coaxial with the pump chamber,
the vent piston is formed coaxially around the pump piston. The
vent piston is formed of the same resilient material as the pump
piston. In a first position of the vent piston relative to the vent
chamber, the peripheral surface of the vent piston engages in a
sealing engagement with the necked down portion of the vent chamber
interior surface at the vent chamber forward end. This seals the
interior of the vent chamber from the exterior environment of the
trigger sprayer, and prevents unintended liquid leakage from the
liquid container attached to the trigger sprayer through the vent
chamber.
[0019] On actuation of the liquid pump, the vent piston moves with
the pump piston. The vent piston moves away from the necked down
portion of the vent chamber interior surface having the smaller
interior diameter, toward the rearward end of the vent chamber.
This movement of the vent piston causes the force of engagement of
the peripheral surface of the vent piston against the interior
surface of the vent chamber to decrease, thereby reducing the drag
on the vent piston peripheral surface as the vent piston moves from
the vent chamber forward end toward the vent chamber rearward end
and through the larger interior diameter portion of the vent
chamber. This reduced drag prevents swelling of the peripheral
surface of the vent piston and/or the vent chamber interior
surface, and prevents binding of the vent piston in the vent
chamber.
[0020] With the novel construction of the venting system of the
invention described above, the trigger sprayer of the invention
overcomes disadvantages commonly associated with prior art trigger
sprayer venting systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Further features of the present invention are set forth in
the following detailed description of the preferred embodiment of
the invention and in the drawing figures wherein:
[0022] FIG. 1 is a side elevation view, in section, of the trigger
sprayer apparatus of the invention in the first, vent closed
position of the vent piston relative to the vent chamber;
[0023] FIG. 2 is an enlarged, partial view of the pump chamber and
vent chamber of FIG. 1 in the vent closed position of the vent
piston; and, FIG. 3 is a view similar to FIG. 3, showing the vent
piston in the vent opened position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0024] FIG. 1 shows a side sectioned view of the trigger sprayer of
the invention that includes the novel venting system of the
invention. Many of the component parts and the details of
construction of the trigger sprayer shown in FIG. 1 are common to
trigger sprayers of the prior art. Therefore, these will only be
described generally. The novel venting system of the invention will
be described in more detail. As is typical in the construction of
trigger sprayers, most of the component parts are constructed of a
plastic material.
[0025] The trigger sprayer comprises a sprayer housing 12 that is
molded with many of the component parts of the trigger sprayer. The
bottom of the sprayer housing 12 is formed with a circular disk 14.
An opening passes through the disk 14 and a liquid supply passage
18 extends upwardly through the sprayer housing from the disk. A
pump chamber 22 is formed on the sprayer housing 12 and
communicates through a pump port 24 with the liquid supply passage
18.
[0026] The pump chamber 22 is defined by a cylindrical side wall 26
of the chamber. The chamber also has a circular end wall 28. The
pump port 24 passes through the end wall 28. The pump chamber side
wall 26 extends from the end wall 28 to a distal end 32 of the side
wall. The side wall distal end 32 surrounds a circular opening into
the interior of the pump chamber. The side wall 26 has a
cylindrical interior surface 34 that defines a center axis 36 of
the pump chamber 22.
[0027] A liquid discharge passage 42 is also formed in the sprayer
housing 12. The liquid discharge passage 42 has a length with a
proximal end 44 that communicates with the liquid supply passage
18, and an opposite distal end 46.
[0028] A check valve 52 is mounted in the sprayer housing 12
adjacent the proximal end 44 of the liquid discharge passage 42.
The check valve 52 permits liquid flow from the pump chamber 22 to
the passage proximal end 44 and to the passage distal end 46, and
prevents the reverse flow.
[0029] As is conventional, a nozzle assembly 54 is mounted to the
distal end 46 of the liquid discharge passage 42.
[0030] Although particular constructions of the check valve 52 and
nozzle assembly 54 are shown in the drawing figures, other
equivalent types of valves and nozzle assemblies may be employed
with the trigger sprayer of the invention.
[0031] A connector cap 62 is formed integrally with the circular
disk 14 of the sprayer housing 12. The cap 62 is used in removably
attaching the sprayer housing 12 to a separate liquid container.
The cap 62 shown has a bayonet fitment for attachment to the liquid
container. However, other equivalent types of connectors may be
employed with the trigger sprayer of the invention.
[0032] A dip tube connector 64 extends upwardly through the cap 62
and through the opening in the bottom disk 14 of the sprayer
housing 12. The dip tube connector 64 forms a portion of the liquid
supply passage 18 that leads to the interior of the pump chamber
22. A valve seat assembly 66 is provided on the upper end of the
dip tube connection 64 as viewed in FIG. 1. A disk valve 68 is
positioned on the seat assembly 66. The disk valve 68 controls the
flow of liquid through the liquid supply passage 18 to the pump
chamber 22. The valve permits the flow of liquid through the supply
passage 18 to the interior of the pump chamber 22, and prevents the
reverse flow of liquid.
[0033] A cylindrical pump piston 72 is mounted in the interior of
the pump chamber 22 for reciprocating movements in the pump
chamber. The pump piston 72 is moveable in the pump chamber 22
between a first position of the piston shown in FIGS. 1 and 2, and
a second position of the piston shown in FIG. 3. A coil spring (not
shown) engages between the piston 72 and the end wall 28 of the
pump chamber, as is conventional. The spring biases the pump piston
72 to its first position. The pump piston 72 is formed integrally
with a piston rod 76 that extends outwardly from the pump piston
and engages with a trigger 82 of the trigger sprayer.
[0034] The trigger 82 has a length with opposite proximal 84 and
distal 86 ends. The trigger proximal end 84 mounts the trigger 82
to the sprayer housing 12 for movement of the trigger relative to
the sprayer housing. Preferably, the trigger 82 pivots relative to
the sprayer housing 12. The operative connection of the trigger 82
to the piston rod 76 and the pump piston 72 causes the
reciprocating movement of the pump piston in the pump chamber 22 in
response to movements of the trigger.
[0035] A shroud 92 covers over much of the exterior of the sprayer
housing 12. The shroud 92 gives an aesthetically pleasing
appearance to the trigger sprayer.
[0036] Much of the construction of the trigger sprayer described to
this point is conventional. The novel venting system of the trigger
sprayer is provided by a vent chamber 94 and a vent piston 96.
[0037] The vent chamber 94 is comprised of a cylindrical side wall
98 and a annular end wall 100. The end wall 100 is coplanar with
and an extension of the pump chamber end wall 28. The vent chamber
side wall 98 extends around and is coaxial with the pump chamber
side wall 26. A vent opening 102 passes through the vent chamber
side wall 98 and communicates an interior volume of the vent
chamber 94 with the interior of the liquid container (not shown)
attached to the trigger sprayer cap 62. The vent chamber side wall
98 has a cylindrical interior surface that defines a center axis of
the vent chamber. The vent chamber center axis is coaxial with the
pump chamber center axis 36. The vent chamber interior surface has
a first surface section 104 that is adjacent a forward end opening
106 to the vent chamber, and a second interior surface section 108
that is adjacent the pump chamber 22. As seen in the drawing
figures, the vent chamber first interior surface section 104 has a
smaller interior diameter dimension than the vent chamber second
interior surface section 108. The axial length of the vent chamber
first interior surface section 104 is shorter than the axial length
of the vent chamber second interior surface section 108. There is a
gradual transition between the smaller diameter of the vent chamber
first interior surface section 104 to the larger interior diameter
of the second interior surface section 108. The second interior
surface section 108 has a substantially constant interior surface
diameter dimension between the first interior surface section 104
and the vent chamber annular end wall 100. A vent passage 112
extends through the vent chamber side wall 96 in the second
interior surface section 108 of the vent chamber.
[0038] The vent piston 96 is an integral part of the pump piston 72
and the piston rod 76. The vent piston 96 is cylindrical and
extends around the pump piston 72. Thus, the vent piston 96 and
pump piston 72 have the same center axis. As seen in FIGS. 1 and 2,
the pump piston 72 is spaced axially and radially inwardly from the
vent piston 96. The vent piston 96 extends radially outwardly from
the piston rod 76 to a resilient peripheral end portion 114 of the
vent piston. This peripheral end portion 114 of the vent piston
engages in a sliding, sealing engagement with the interior surfaces
104, 108 of the vent chamber 94. As seen in FIG. 1, the vent piston
end portion 114 tapers slightly radially away from the remainder of
the vent piston 94 as it extends to the distal end of the vent
piston. This provides for a resilient sealing engagement of the
vent piston peripheral end portion 114 with both the first interior
surface section 104 and the second interior surface section 108 of
the vent chamber interior surface.
[0039] Because the vent chamber first interior surface section 104
has a smaller interior diameter dimension than the vent chamber
second interior surface section 108, the vent piston peripheral
edge portion 114 exerts a greater force against the vent chamber
first interior surface section 104 than the vent chamber second
interior surface section 108. This assures a sealing engagement
between the vent piston peripheral end portion 114 and the vent
chamber first interior surface section 104 when the trigger sprayer
is not in use. Thus, this ensures against the unintended leakage
from the trigger sprayer attached to a liquid container if the
sprayer and container should be positioned in an orientation that
would cause liquid to exit the top of the container and pass
through the vent opening 102 into the vent chamber 94.
[0040] When the trigger sprayer is operated, the vent piston
peripheral end portion 114 moves from engagement with the vent
chamber first interior surface section 104 to engage with the vent
chamber second interior surface section 108. Although the
engagement of the vent piston peripheral edge portion 114 in both
the vent chamber first interior surface section 104 and second
interior surface section 108 provides a sealing engagement that
prevents the leakage of liquid through the vent chamber open end
106, the engagement force of the vent piston peripheral end portion
114 in the vent chamber second interior surface section 108 is less
than that in the vent chamber first interior surface section 104.
This reduces the drag or friction force exerted on the vent piston
peripheral end portion 114 in the vent chamber second interior
surface section 108. This reduced drag or friction force on the
vent piston peripheral end portion eliminates the concern of
swelling of the vent piston peripheral end portion 114 or swelling
of the vent chamber sidewall 98, which could increase the force of
engagement of the vent piston against the interior surface of the
vent chamber and result in binding of the vent piston in the vent
chamber.
[0041] On operation of the trigger sprayer, as the trigger 82 is
squeezed to the second position shown in FIG. 3, the vent piston 96
moves to its second position relative to the vent chamber 94. In
the second position of the vent piston 96, the piston is moved
through the vent chamber second interior surface section 108. The
drag or friction force exerted on the vent piston peripheral edge
114 is reduced due to the increased diameter dimension of the vent
chamber second interior surface section 108. The vent piston moves
until the peripheral surface portion 114 passes over the vent
chamber opening 102 that communicates through a vent passage 112
with the container interior. In the second position of the vent
piston 94 shown in FIG. 3, the peripheral surface portion 114 of
the vent piston has moved across the vent opening 102. This
provides a flow path of venting air from the exterior environment
of the trigger sprayer through the vent chamber 94 between the vent
piston 96 and the vent chamber side wall 98, and through the vent
chamber opening 102 to the interior of the liquid container
connected to the trigger sprayer. In this manner, on operation of
the liquid pump of the trigger sprayer, the interior of the liquid
container connected to the trigger sprayer is vented.
[0042] On release of the trigger 82, the coil spring (not shown)
returns both the pump piston 72 and vent piston 96 to their
positions shown in FIGS. 1 and 2. In the position of the vent
piston 96 shown in FIGS. 1 and 2, the peripheral surface portion
114 of the vent piston again engages in sealing engagement with the
first interior surface section 104 of the vent chamber side wall
98, thus sealing the interior of the vent chamber 94 from the
exterior environment of the sprayer.
[0043] With the novel construction of the venting system of the
invention described above, the trigger sprayer of the invention
overcomes disadvantages commonly associated with prior art trigger
sprayer venting systems.
[0044] Although the trigger sprayer of the invention has been
described above with reference to a specific embodiment of the
sprayer, it should be understood that other variations of the
sprayer may be arrived at without departing from the invention's
scope of protection provided by the following claims.
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